Our goal is to further characterize the role and mechanisms (molecular, neuroanatomical, and physiological) of hormones in the development, activation and control of the neural and peripheral systems involved in sexual and fighting behavior and adenohypophysial hormone secretion in the rat and mouse. This work involves the extensive use of stereotaxic surgery to localize the sites of hormone activation and/or metabolism. In doing these studies we rely heavily on enzyme blockers and anti-hormones. The sites for implantation have been selected on the basis of our studies using radiolabeled hormones in which we conduct regional analyses of hormone concentrations in subcellular fractions. We are also actively involved in work using radioenzymatic assays for the various monoamine neurotransmitters in discrete regions of the brain. These studies have as their endpoint either a behavioral assay for sexual or fighting behavior or radioimmuno or bioassay of various adenohypophysial hormones.